poj2436

位操作枚举

#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>
using namespace std;

#define maxn 1005

int n, d, k;
int cow[maxn];

bool ok(int a)
{
    int ret = 0;
    while (a)
    {
        ret += (a & 1);
        a >>= 1;
    }
    return ret == k;
}

int main()
{
    //freopen("t.txt", "r", stdin);
    scanf("%d%d%d", &n, &d, &k);
    for (int i = 0; i < n; i++)
    {
        int a, b;
        scanf("%d", &a);
        for (int j = 0; j < a; j++)
        {
            scanf("%d", &b);
            cow[i] |= (1 << (b - 1));
        }
    }
    int s = (1 << k) - 1;
    int e = s << (d - k);
    int ans = 0;
    for (int i = s; i <= e; i++)
        if (ok(i))
        {
            int temp = 0;
            for (int j = 0; j < n; j++)
                if ((cow[j] & i) == cow[j])
                    temp++;
            ans = max(ans, temp);
        }
    printf("%d\n", ans);
    return 0;
}